Keep all_jobs_used consistent

Only decrement all_jobs_used when we actually remove a job from the hash

If a job does not have an id then it is not in the hash so do not attempt
to remove it. Such temp jobs are used in prot.c to return stats

job.c

@@ -158,25 +158,26 @@ job_hash_free(job j)
  if (jh == j) {
  /* Special case the first */
  all_jobs[index] = jh->ht_next;
+ all_jobs_used--;
  } else {
  job tmp;
  while (jh->ht_next && jh->ht_next != j) jh = jh->ht_next;
  if (jh->ht_next) {
+ all_jobs_used--;
  tmp = jh->ht_next;
  jh->ht_next = jh->ht_next->ht_next;
  }
  }
  }
 
- all_jobs_used--;
 }
 
 void
 job_free(job j)
 {
  if (j) {
  TUBE_ASSIGN(j->tube, NULL);
- job_hash_free(j);
+ if (j->id) job_hash_free(j);
  }
 
  free(j);